The effect of a low-energy food foam on appetite measures during a 1-day reduced-energy meal plan.

BACKGROUND/OBJECTIVES: We have previously shown that 500 ml of a foamed drink ('foam') significantly improved appetite versus a non-foamed control. The objectives of this research were to assess the effect of smaller volumes of foams on appetite, and the potential benefits of foam ingestion and its timing on appetite measures in a reduced-energy context. SUBJECTS/METHODS: Two randomized, parallel design studies (pre- and main study) were conducted using healthy adult subjects. Pre-study: 133 subjects (age 18-50 years, body mass index (BMI) 20-32 kg m(-2)) each consumed either 10, 25, 50, 100, 150 or 250 ml foamed meal replacer (~0.2 kcal ml(-1)), 150 min after a fixed breakfast. Main study: four groups of subjects (n=134; age 18-60 years, BMI 22.5-35.0 kg m(-2)) consumed 200 ml/22 kcal foam (based on pre-study results) immediately after main meals (M), after snacks (S), in-between snacks and main meals (I) or not at all (control, C) within 1 day of a reduced-energy meal plan consisting of three main meals and three snacks. Measurements included self-reported appetite (six scales, reported as area under the curve (AUC)) and (main study only) end-of-day appetite questionnaire. RESULTS: Pre-study: the strongest effect on appetite was produced by 250 ml (consistent across scales), whereas 150 ml showed more pronounced effects than 100 and 50 ml in most scales. Volumes 10 and 25 ml had no effects on any scale. Main study: 200 ml foam reduced appetite AUC substantially in all treatments, particularly M (for example, hunger AUC reduced by 35% (P <0.001), 28% (P <0.05) and 20% (P=0.11) for M, S and I, respectively versus C). A strong reduction in 'appetite for a snack' was seen for all timings (all P <0.05). The end-of-day appetite ratings confirmed these findings. CONCLUSIONS: Modest amounts of a low-energy foam can reduce appetite measures during a 1-day reduced-energy meal plan.

The effect of protease inhibitors derived from potato formulated in a minidrink on appetite, food intake and plasma cholecystokinin levels in humans.

BACKGROUND: Protease inhibitor 2 derived from potato (PI2) is claimed to reduce appetite and food intake, stimulate the satiety hormone cholecystokinin (CCK) and lower postprandial glucose peaks when taken before a meal. However, current literature is inconclusive with regard to its efficacy and mechanism. Furthermore, the potential effect of PI2 on appetite motivational ratings without an immediately following meal has not previously been reported. OBJECTIVE: To comprehensively test the effects of 30 mg PI2 in a minidrink on appetite ratings, subsequent food intake, and plasma CCK and glucose responses. DESIGN: Minidrinks with or without 30 mg PI2 were compared in three separate substudies (A, B and C), each using a two-way, placebo-controlled, balanced-order, cross-over design and 23 or 24 subjects (mean over groups: body mass index 25.0 kg m(-2), range 22.5-30.7 kg m(-2); age 41.3, range 18-62 years). The minidrink was given (A) 120 or (B) 30 min before an ad libitum lunch or (C) 30 min before a fixed lunch. Study parameters were self-reported satiety (substudies A and C), ad libitum meal intake (substudies A and B), and (in an n=12 subset) plasma CCK and blood glucose in all substudies. All results were analyzed using analysis of covariance. Protease-inhibitory activity of the PI2-containing minidrinks was assessed under simulated gut conditions. RESULTS: PI2 did not differ from control for any study parameters, in any substudy, despite confirmation of the inhibitory activity of PI2. CONCLUSIONS: In this study protease inhibition using PI2 in a minidrink at a dose of 30 mg, as commercially used, had no (functional) efficacy on a range of behavioral and physiological appetite and intake control measures.

Effect of ileal fat perfusion on satiety and hormone release in healthy volunteers.

OBJECTIVE: The ileal brake is a feedback mechanism activated by nutrients, especially fat, with marked effects on satiety. The effects of low doses of ileal fat on satiety are largely unknown. We therefore studied the effect of ileal vs oral delivery of low doses of fat on satiety and gut peptide secretion. DESIGN: Randomized, single-blind crossover design. SUBJECTS: Sixteen healthy, normal-weight volunteers (6 male; mean age 26 years, mean body mass index 22.4). INTERVENTION: Participants were intubated with a 290-cm-long nasoileal tube and consumed, on 3 consecutive days, either a liquid breakfast with 3 g fat followed by an ileal placebo infusion at t=105-150 min (treatment C) or a fat-free liquid breakfast followed by an ileal infusion of either an emulsion of 3 g (treatment 13 g) or 9 g (treatment 19 g) fat (safflower oil). MEASUREMENTS: Satiety parameters by visual analog scales and plasma concentrations of CCK and PYY. RESULTS: C significantly increased satiety and CCK secretion compared with the fat-free breakfast. Ileal fat perfusion of both 3 and 9 g 13 g and 19 g) significantly increased satiety during and after fat perfusion, without differences in satiety between 13 g and 19 g. During ileal fat infusion, CCK increased dose dependently, whereas PYY concentrations increased significantly only after 9 g of fat. Secretion of CCK but not of PYY correlated to satiety levels. CONCLUSION: Postprandial satiety following a liquid breakfast can be effectively and significantly increased by small amounts (as little as 3 g) of fat perfused into the ileum. Ileal fat dose-dependently increased CCK but not PYY secretion. The satiating effect of ileal fat may be partly mediated by CCK.

Ileal brake: a sensible food target for appetite control. A review.

With the rising prevalence of obesity and related health problems increases, there is increased interest in the gastrointestinal system as a possible target for pharmacological or food-based approaches to weight management. Recent studies have shown that under normal physiological situations undigested nutrients can reach the ileum, and induce activation of the so-called "ileal brake", a combination of effects influencing digestive process and ingestive behaviour. The relevance of the ileal brake as a potential target for weight management is based on several findings: First, activation of the ileal brake has been shown to reduce food intake and increase satiety levels. Second, surgical procedures that increase exposure of the ileum to nutrients produce weight loss and improved glycaemic control. Third, the appetite-reducing effect of chronic ileal brake activation appears to be maintained over time. Together, this evidence suggests that activation of the ileal brake is an excellent long-term target to achieve sustainable reductions in food intake. This review addresses the role of the ileal brake in gut function, and considers the possible involvement of several peptide hormone mediators. Attention is given to the ability of macronutrients to activate the ileal brake, and particularly variation attributable to the physicochemical properties of fats. The emphasis is on implications of ileal brake stimulation on food intake and satiety, accompanied by evidence of effects on glycaemic control and weight loss.

Effect of carbohydrate digestibility on appetite and its relationship to postprandial blood glucose and insulin levels.

BACKGROUND/OBJECTIVES: 'Slowly digestible' carbohydrates have been claimed to reduce appetite through their effects on postprandial glucose and insulin levels, but literature is inconsistent. The inconsistencies between studies might be explained by factors other than glycemic effects per se, for example, nutritional or physical properties. We tested this possibility by examining postprandial glucose, insulin and appetite responses to drinks differing only in rate and extent of digestibility of carbohydrates. This was accomplished by comparing different glucose polymers: maltodextrin (rapidly digestible) versus medium-chain pullulan (slowly but completely digestible) versus long-chain pullulan (indigestible). SUBJECTS/METHODS: In a randomized double-blind balanced crossover design, 35 subjects received drinks with 15 g test carbohydrate polymers. Key outcome measures were appetite scores, digestibility (in vitro test and breath hydrogen), and (in a subset) glucose and insulin levels. RESULTS: Digestibility, glucose and insulin data confirmed the rapid, slow and nondigestible nature of the test carbohydrates. Despite its low digestibility, only long-chain pullulan reduced appetite compared with the maltodextrin control, whereas the medium-chain pullulan did not. CONCLUSIONS: We conclude that glycemic responses per se have minimal effects on appetite, when tested in products differing in only carbohydrate digestibility rate and extent.

No efficacy of processed Fabuless (Olibra) in suppressing appetite or food intake.

BACKGROUND/OBJECTIVES: To investigate the feasibility of Fabuless (previously called Olibra and Reducal) as a food ingredient for food intake and appetite reduction, by assessing the effects of food processing on efficacy. SUBJECTS/METHODS: In total, 24 healthy volunteers (16 female, 8 male; age: 18-43 years; body mass index: 18-37 kg/m(2)) took part in a randomized, placebo-controlled, double-blinded, cross-over trial. Yoghurt-based meal replacement drinks (containing processed or unprocessed Fabuless, or a control fat) were followed by an ad libitum lunch and evening meal (dinner). Key outcome measures were energy intake and self-reported appetite ratings. RESULTS: Compared with control, only unprocessed Fabuless reduced subsequent energy intake, although only during dinner (P < 0.01; control, processed and unprocessed: 4.3, 3.9 and 4.2 MJ, respectively) and not during lunch (3.6, 3.7 and 3.6 MJ). Self-reported appetite scores did not differ between treatments. CONCLUSIONS: Although modest effects of unprocessed Fabuless were seen on food intake, but not on appetite, the ingredient was not robust to common food-manufacturing processes (thermal and shear processing). Claims on reduced food intake and appetite relating to this ingredient in food products are, therefore, only valid if functionality has been demonstrated after all relevant processing and storage steps.

Gastrointestinal targets of appetite regulation in humans.

The aim of this paper is to describe and discuss relevant aspects of the assessment of physiological functions - and related biomarkers - implicated in the regulation of appetite in humans. A short introduction provides the background and the present state of biomarker research as related to satiety and appetite. The main focus of the paper is on the gastrointestinal tract and its functions and biomarkers related to appetite for which sufficient data are available in human studies. The first section describes how gastric emptying, stomach distension and gut motility influence appetite; the second part describes how selected gastrointestinal peptides are involved in the control of satiety and appetite (ghrelin, cholecystokinin, glucagon-like peptide, peptide tyrosin-tyrosin) and can be used as potential biomarkers. For both sections, methodological aspects (adequacy, accuracy and limitation of the methods) are described. The last section focuses on new developments in techniques and methods for the assessment of physiological targets involved in appetite regulation (including brain imaging, interesting new experimental approaches, targets and markers). The conclusion estimates the relevance of selected biomarkers as representative markers of appetite regulation, in view of the current state of the art.

Review article: The gastrointestinal tract: neuroendocrine regulation of satiety and food intake.

BACKGROUND: The gastrointestinal tract elicits numerous signals regulating food intake and satiety, and recently many studies have been performed to elucidate the mechanisms regulating these signals. AIM: To describe the effects of the gastrointestinal tract on satiety, satiation and food intake. METHODS: A PubMed search was performed to identify and select the relevant literature using search terms including 'gastric satiety, intestine + satiety, satiation, cholecystokinin, ghrelin, peptide YY, glucagon-like peptide-1 and ileal brake'. RESULTS: Satiation, satiety and food intake result, among other factors, from signals originating in the stomach caused by distension and signals from the small intestine. These intestinal signals result from nutrient sensing in the gut and activate neural and humoral pathways. Activation of the distal part of the gut, the so called ileal brake, leads to reduction in hunger and food intake, and models of chronic ileal brake activation lead to massive weight loss. CONCLUSION: Gastrointestinal signals are crucial for the regulation of food intake, satiety and satiation. The ileal brake deserves special attention, as both ileal intubation studies and surgical studies demonstrate that activation of the ileal brake reduces food intake. In the surgical models, weight loss occurs without adaptation to the anorectic effects of ileal brake activation.